IPAC2015 - List of Authors (Latina, A.)

Paper	Title	Page
MOPJE059	Tests of Wakefield-Free Steering at ATF2	438
	A. Latina, J. Pfingstner, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway N. Fuster-Martínez IFIC, Valencia, Spain J. Snuverink JAI, Egham, Surrey, United Kingdom
	Charge-dependent effects on the orbit and on the beam size affect the performance of the Accelerator Test Facility (ATF2) in a non-negligible way. Until now small beam sizes have only been achieved running with a beam charge significantly smaller than the nominal value. These detrimental effects on the beam have been attributed to wakefields, in the cavity BPMs, in the multi-Optical Transition Radiation (OTR) systems as well as in other components of the beamline. The successful tests of a Wakefield-free Steering (WFS) algorithm at FACET have encouraged performing tests of the same correction scheme at ATF2. The performance of the algorithm has been simulated in detail, including several realistic imperfection scenarios, including charge-dependent BPMs resolution, and incoming injection error and position jitters, which are described in this paper. Tests of WFS have been performed at ATF2 during December 2014. The results are discussed here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE059
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MOPJE060	BBA and Coupling Correction at CLIC RTML	442
	Y. Han, L. Ma SDU, Shandong, People's Republic of China A. Latina, D. Schulte CERN, Geneva, Switzerland
	The CLIC Ring To Main Linac (RTML) must transport the electron and the positron bunches through more than 20 km of beamlines with minimal emittance growth. The turnaround loops (TAL) are one of the most critical sections, featuring a lattice designed to minimize emittance growth due to synchrotron radiation emission and chromaticity, while being isochronous to avoid bunch lengthening. With such a design, the impact of static imperfections like element misalignment is particularly critical. In this paper a study of the Beam-Based Alignment (BBA) techniques in the TAL of the CLIC RTML is presented. In order to reduce the emittance growth, the one-to-one and dispersion-free corrections have been tested. The results showed that the emittance growth budgets can be met both in the horizontal and vertical planes. The impact of coupling errors due to magnets rolls on the emittance has also been studied and a coupling correction section has been designed and inserted in the lattice.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE060
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MOPJE066	Single and Multi-bunch End-to-end Tracking in the LHeC	459
	D. Pellegrini, A. Latina, D. Schulte CERN, Geneva, Switzerland S.A. Bogacz JLab, Newport News, Virginia, USA
	The LHeC study aims at delivering an electron beam for collision with the LHC proton beam. The current baseline design consists of a multi-pass superconductive energy-recovery linac operating in a continuous wave mode. The high current beam (~100 mA) in the linacs excites long-range wake-fields between bunches of different turns, which induce instabilities and might cause beam losses. PLACET2, a novel version of the tracking code PLACET, capable to handle recirculation and time dependencies, has been employed to perform the first LHeC end-to-end tracking. The impact of long-range wake-fields, synchrotron radiation, and beam-beam effects has been assessed. The simulation results and recent improvements in the lattice design are presented and discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE066
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MOPJE067	Applications of PLACET2 to the CTF3 Combiner Ring	462
	D. Pellegrini, R. Corsini, D. Gamba, A. Latina CERN, Geneva, Switzerland
	The CTF3 Combiner Ring (CR) is an isochronous ring that employs RF-injection to combine multiple bunch trains (up to five) into a single one with higher bunch frequency. The length of the CR plays a critical role in obtaining the correct structure of the recombined train. PLACET2: the new recirculating version of the code PLACET is particularly suited to simulate the operational scenario. In order to validate this code, three different case studies have been considered: ring-length variations due to energy detuning, fast-beam decoherence due to uncorrected chromatic effects and vertical instabilities due to bunch-to-bunch wakefield effects. The first two effects have been measured during the last run and the predictions have been validated. The instability has been compared with previous studies. The results are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE067
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MOPJE068	PLACET2: A Novel Code for Beam Dynamics in Recirculating Machines	465
	D. Pellegrini, A. Latina, D. Schulte CERN, Geneva, Switzerland
	Efforts have been taken to enable the simulation of recirculating machines in PLACET. The new version, PLACET2, allows handling multiple interconnected beamlines in order to obtain a realistic model of a machine. Two new elements, injectors and dumps, have been introduced and are active components of any working machine. Trains of bunches are routed through beamlines and tracked simultaneously in a parallel manner. Tracking through time-dependent elements is possible, and care is made to preserve the correct time-structure of the beam in case of beam recombination. This allows straightforward computations of multi-bunch effects arising with high-charge and shortly spaced bunch trains, even with variable train structure. The main features of the code are presented together with its working principles and its key ideas. Two case studies are introduced: LHeC and the CTF3 combiner ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE068
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TUPWA005	Comparison of Bunch Compression Schemes for the AXXS FEL	1399
	T.K. Charles, D.M. Paganin Monash University, Faculty of Science, Clayton, Victoria, Australia A.A. Aksoy Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey M.J. Boland, R.T. Dowd SLSA, Clayton, Australia A. Latina, D. Schulte CERN, Geneva, Switzerland
	Different types of electron bunch compression schemes are compared for the AXXS FEL design study. The main linac for the proposed machine is based on CLIC x-band structures. This choice leaves several options for the bunch compression schemes which impact the injection system RF band. Both harmonic linearization and phase modulation linearization are considered and their relative strengths and weaknesses compared. Simulations were performed to compare the performance of an s-band injector with a higher harmonic RF linearization and an x-band injector. One motivation for the study is to optimise the length of the AXXS machine, allowing the linac to fit onto the proposed and also act as the injector to the existing storage ring at the Australian Synchrotron.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA005
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TUPTY032	Study of Muon Backgrounds in the CLIC Beam Delivery System	2075
	F.B. Pilicer, E. Pilicer, İ. Tapan UU, Bursa, Turkey H. Burkhardt, L. Gatignon, A. Latina, D. Schulte, R. Tomás CERN, Geneva, Switzerland
	We describe the detailed modelling of muon background generation and absorption in the CLIC beam delivery system. The majority of the background muons originates in the first stages of halo collimation. We also discuss options to use magnetised cylindrical iron shields to reduce the muon background flux reaching the detector region.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY032
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TUPTY056	Beam-Based Measurements of Long Range Transverse Wakefields in CLIC Main Linac Accelerating Structure	2153
	H. Zha, A. Grudiev, A. Latina, D. Schulte, A. Solodko, W. Wuensch CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway G. De Michele EPFL, Lausanne, Switzerland G. De Michele PSI, Villigen PSI, Switzerland N. Lipkowitz, G. Yocky SLAC, Menlo Park, California, USA
	The baseline design of CLIC (Compact Linear Collider) uses X-band accelerating structures in the main linac. Every accelerating structure cell has four waveguides, terminated with individual RF loads, to damp the unwanted long-range transverse wakefields, in order to maintain beam stability in multi-bunch operation. In order to experimentally verify the calculated suppression of the wakefields, a prototype structure has been built and installed in FACET test facility at SLAC. The results of the measurements of the wakefields in the prototype structure by means of positron and electron bunches are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY056
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THPF101	Design of a Proton Travelling Wave Linac with a Novel Tracking Code	3945
	S. Benedetti EPFL, Lausanne, Switzerland U. Amaldi TERA, Novara, Italy A. Grudiev, A. Latina CERN, Geneva, Switzerland
	A non-relativistic proton linac based on high gradient backward travelling wave accelerating structures was designed using a novel dedicated 3D particle tracking code. Together with the specific RF design approach adopted, the choice of a 2.9985 GHz backward travelling wave (BTW) structure with 150° RF phase advance per cell was driven by the goal of reaching an accelerating gradient of 50 MV/m, which is more than twice that achieved so far. This choice dictated the need to develop a new code for tracking charged particles through travelling wave structures which were never used before in proton linacs. Nevertheless, the new code has the capability of tracking particles through any kind of accelerating structure, given its real and imaginary electromagnetic field map. This project opens a completely new field in the design of compact linacs for proton therapy, possibly leading to cost-effective and widespread single room facilities for cancer treatment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF101
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Paper

Title

Page

Tests of Wakefield-Free Steering at ATF2

438

A. Latina, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway
N. Fuster-Martínez
IFIC, Valencia, Spain
J. Snuverink
JAI, Egham, Surrey, United Kingdom

Charge-dependent effects on the orbit and on the beam size affect the performance of the Accelerator Test Facility (ATF2) in a non-negligible way. Until now small beam sizes have only been achieved running with a beam charge significantly smaller than the nominal value. These detrimental effects on the beam have been attributed to wakefields, in the cavity BPMs, in the multi-Optical Transition Radiation (OTR) systems as well as in other components of the beamline. The successful tests of a Wakefield-free Steering (WFS) algorithm at FACET have encouraged performing tests of the same correction scheme at ATF2. The performance of the algorithm has been simulated in detail, including several realistic imperfection scenarios, including charge-dependent BPMs resolution, and incoming injection error and position jitters, which are described in this paper. Tests of WFS have been performed at ATF2 during December 2014. The results are discussed here.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPJE060

BBA and Coupling Correction at CLIC RTML

442

Y. Han, L. Ma
SDU, Shandong, People's Republic of China
A. Latina, D. Schulte
CERN, Geneva, Switzerland

The CLIC Ring To Main Linac (RTML) must transport the electron and the positron bunches through more than 20 km of beamlines with minimal emittance growth. The turnaround loops (TAL) are one of the most critical sections, featuring a lattice designed to minimize emittance growth due to synchrotron radiation emission and chromaticity, while being isochronous to avoid bunch lengthening. With such a design, the impact of static imperfections like element misalignment is particularly critical. In this paper a study of the Beam-Based Alignment (BBA) techniques in the TAL of the CLIC RTML is presented. In order to reduce the emittance growth, the one-to-one and dispersion-free corrections have been tested. The results showed that the emittance growth budgets can be met both in the horizontal and vertical planes. The impact of coupling errors due to magnets rolls on the emittance has also been studied and a coupling correction section has been designed and inserted in the lattice.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE060

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPJE066

Single and Multi-bunch End-to-end Tracking in the LHeC

459

D. Pellegrini, A. Latina, D. Schulte
CERN, Geneva, Switzerland
S.A. Bogacz
JLab, Newport News, Virginia, USA

The LHeC study aims at delivering an electron beam for collision with the LHC proton beam. The current baseline design consists of a multi-pass superconductive energy-recovery linac operating in a continuous wave mode. The high current beam (~100 mA) in the linacs excites long-range wake-fields between bunches of different turns, which induce instabilities and might cause beam losses. PLACET2, a novel version of the tracking code PLACET, capable to handle recirculation and time dependencies, has been employed to perform the first LHeC end-to-end tracking. The impact of long-range wake-fields, synchrotron radiation, and beam-beam effects has been assessed. The simulation results and recent improvements in the lattice design are presented and discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE066

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPJE067

Applications of PLACET2 to the CTF3 Combiner Ring

462

D. Pellegrini, R. Corsini, D. Gamba, A. Latina
CERN, Geneva, Switzerland

The CTF3 Combiner Ring (CR) is an isochronous ring that employs RF-injection to combine multiple bunch trains (up to five) into a single one with higher bunch frequency. The length of the CR plays a critical role in obtaining the correct structure of the recombined train. PLACET2: the new recirculating version of the code PLACET is particularly suited to simulate the operational scenario. In order to validate this code, three different case studies have been considered: ring-length variations due to energy detuning, fast-beam decoherence due to uncorrected chromatic effects and vertical instabilities due to bunch-to-bunch wakefield effects. The first two effects have been measured during the last run and the predictions have been validated. The instability has been compared with previous studies. The results are presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE067

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPJE068

PLACET2: A Novel Code for Beam Dynamics in Recirculating Machines

465

D. Pellegrini, A. Latina, D. Schulte
CERN, Geneva, Switzerland

Efforts have been taken to enable the simulation of recirculating machines in PLACET. The new version, PLACET2, allows handling multiple interconnected beamlines in order to obtain a realistic model of a machine. Two new elements, injectors and dumps, have been introduced and are active components of any working machine. Trains of bunches are routed through beamlines and tracked simultaneously in a parallel manner. Tracking through time-dependent elements is possible, and care is made to preserve the correct time-structure of the beam in case of beam recombination. This allows straightforward computations of multi-bunch effects arising with high-charge and shortly spaced bunch trains, even with variable train structure. The main features of the code are presented together with its working principles and its key ideas. Two case studies are introduced: LHeC and the CTF3 combiner ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE068

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPWA005

Comparison of Bunch Compression Schemes for the AXXS FEL

1399

T.K. Charles, D.M. Paganin
Monash University, Faculty of Science, Clayton, Victoria, Australia
A.A. Aksoy
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
M.J. Boland, R.T. Dowd
SLSA, Clayton, Australia
A. Latina, D. Schulte
CERN, Geneva, Switzerland

Different types of electron bunch compression schemes are compared for the AXXS FEL design study. The main linac for the proposed machine is based on CLIC x-band structures. This choice leaves several options for the bunch compression schemes which impact the injection system RF band. Both harmonic linearization and phase modulation linearization are considered and their relative strengths and weaknesses compared. Simulations were performed to compare the performance of an s-band injector with a higher harmonic RF linearization and an x-band injector. One motivation for the study is to optimise the length of the AXXS machine, allowing the linac to fit onto the proposed and also act as the injector to the existing storage ring at the Australian Synchrotron.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY032

Study of Muon Backgrounds in the CLIC Beam Delivery System

2075

F.B. Pilicer, E. Pilicer, İ. Tapan
UU, Bursa, Turkey
H. Burkhardt, L. Gatignon, A. Latina, D. Schulte, R. Tomás
CERN, Geneva, Switzerland

We describe the detailed modelling of muon background generation and absorption in the CLIC beam delivery system. The majority of the background muons originates in the first stages of halo collimation. We also discuss options to use magnetised cylindrical iron shields to reduce the muon background flux reaching the detector region.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY056

Beam-Based Measurements of Long Range Transverse Wakefields in CLIC Main Linac Accelerating Structure

2153

H. Zha, A. Grudiev, A. Latina, D. Schulte, A. Solodko, W. Wuensch
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway
G. De Michele
EPFL, Lausanne, Switzerland
G. De Michele
PSI, Villigen PSI, Switzerland
N. Lipkowitz, G. Yocky
SLAC, Menlo Park, California, USA

The baseline design of CLIC (Compact Linear Collider) uses X-band accelerating structures in the main linac. Every accelerating structure cell has four waveguides, terminated with individual RF loads, to damp the unwanted long-range transverse wakefields, in order to maintain beam stability in multi-bunch operation. In order to experimentally verify the calculated suppression of the wakefields, a prototype structure has been built and installed in FACET test facility at SLAC. The results of the measurements of the wakefields in the prototype structure by means of positron and electron bunches are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPF101

Design of a Proton Travelling Wave Linac with a Novel Tracking Code

3945

S. Benedetti
EPFL, Lausanne, Switzerland
U. Amaldi
TERA, Novara, Italy
A. Grudiev, A. Latina
CERN, Geneva, Switzerland

A non-relativistic proton linac based on high gradient backward travelling wave accelerating structures was designed using a novel dedicated 3D particle tracking code. Together with the specific RF design approach adopted, the choice of a 2.9985 GHz backward travelling wave (BTW) structure with 150° RF phase advance per cell was driven by the goal of reaching an accelerating gradient of 50 MV/m, which is more than twice that achieved so far. This choice dictated the need to develop a new code for tracking charged particles through travelling wave structures which were never used before in proton linacs. Nevertheless, the new code has the capability of tracking particles through any kind of accelerating structure, given its real and imaginary electromagnetic field map. This project opens a completely new field in the design of compact linacs for proton therapy, possibly leading to cost-effective and widespread single room facilities for cancer treatment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF101

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)